Wannafbody:
You had a foot of snow on your truck? That's lot of snow to remove by brushing.
Your method of freeze-dry "washing" is kind of what I do to wash my unattached garage floor of salt residue when it is much too cold to actually wash the floor with a floor degreaser soap and water. Works OK to get the majority of the salt brine residue and fine sand andyes, the snow I have to shovel in is very dry and powdery to do this. The salt residue does melt the snow, so I have a small floor squeegee to wipe out this slush AFTER I have swept out the snow with a shop push brush. At least it prevents tracking in the salt residue getting into the parked vehicles in the garage. And yes, it has been EXTREMELY cold in Green Bay, WI (-18°F ambient temp with a wind-chill of - 35°F on Monday morning of the 26th Jan, 2026), so it is even too cold for garbage floor cleaning.
And yes most daily-driven vehicles are wearing their winter ermine "white coats", and some vehicle's actual colors are difficult to determine. Automatic car washes will get slammed this weekend when temps return to a more winter-normal of 20-25°F.
Right now a clean vehicle sticks out like a shirtless Packer football fan at a December game at The Frozen Tundra of Lambeau Field.